Hello there!
I'm trying to quantify monoamine metabolites (5-HT, 5-HTP, 5-HIAA
and 3-OMD, DA) in human ventricular CSF. But there're huge peaks
of unknow substances in CSF that make the HPLC system inundated.
The system I'm using is ESA Coulochem II HPLC system interfaced
with ESA 1090A EC coulometric redox detectors. The columns are
15 cm, 5 micron ESA C-18 reverse phase columns. The mobile phase
is a potassium phosphate buffer made by ESA (MD-TM mobile phase).
Could anybody help me figure out how to get rid those inundating
peaks? It could be proteins, but after tried different concentrations
of PCA the peaks are still there.
Please, please help me! Thanks in advance.
Howard